Download or purchase a recording program. If you don't record things very often or if you aren't very interested in getting into recording, download a free basic program. If you want to get into recording, you might want to purchase a quality recording program for future use. Install whatever program you get and open it.
Import the project file into your recording program. If you have compatibility problems, do a basic search engine search to convert the files you have into the files you need. If the files are in .wav format (unrendered), you shouldn't have any problem importing the project.
Find out which tracks are vocal tracks. There are probably multiple vocal tracks, even if it doesn't sound like it on the recording. You have to take lead vocals, background vocals and layered vocals into consideration.
Mute the vocal tracks in your recording program by clicking the "M" button next to each vocal track. When the button is red, that means the track is muted. Most recording programs have the mute button. Don't delete the tracks because you might need the original file at some point in the future, according to computermusictutorials.com.
Export the project once you mute all vocal tracks. In all cases, export the project in MP3 format.